The invention concerns a tire-pressure monitoring device. The present state of the art discloses mechanical sensing devices that emit a signal on collapse of a tire. However, such devices have the disadvantage that they are very susceptible to external disturbances, give a warning only when the tire pressure has already dropped to very low critical values, and cannot be employed with dual tires since there is no collapse in the case of failure of one tire because the second tire then takes over the entire load.